Method of forming electrical connectors

ABSTRACT

A method is disclosed for forming electrical connectors in individual and strip form. The connector is formed from a metal strip by punching from the strip two fingers which are integrally connected to the strip at the fingers&#39;&#39; base. The fingers are bent about their bases so that they overlie the material of the strip. The strip is then tubulated so that the fingers extend into the hollow of the tubulated strip. The tubulated strip is shaped by a die swaging technique to form a top connector portion and a bottom nose portion. Waste material is removed to form a finished electrical connector.

United States Patent Hall [54] METHOD OF FORMING ELECTRICAL CONNECTORS [72] Inventor: Bartley E. Hall, Newtown, Conn.

[73] Assignee: Auto-Swage Products, Inc., Shelton, Conn.

[22] Filed: July 25, 1969 [21] Appl. N0.: 845,024

[ 51 May 30, 1972 Primary Examiner-John F. Campbell Assistant Examiner-Donald P. Rooney Attorney-Finnegan, Henderson & Farabow [5 7] ABSTRACT A method is disclosed for forming electrical connectors in individual and strip form. The connector is formed from a metal strip by punching from the strip two fingers which are integrally connected to the strip at the fingers base. The fingers are bent about their bases so that they overlie the material of the strip. The strip is then tubulated so that the fingers extend into the hollow of the tubulated strip. The tubulated strip is shaped by a die swaging technique to form a top connector portion and a bottom nose portion. Waste material is removed to form a finished electrical connector.

10 Claims, 7 Drawing Figures PATENTEUmsomz 3.665.600

- saw 1 or 2 mvmwon BARTLEY E. HALL image/2, f/e/zc/wso/z Qja oa) ATTORN EYS PATENTEDMAY 30 1972 SHEET 20F 2 FIG. 4

mvmwon BARTLEY E- HALL 3721263620, J /e/zdmo/z ($50600,

ATTORNEYS METHOD OF FORMING ELECTRICAL CONNECTORS This invention relates to electrical connectors and more particularly to a method of forming electrical connectors, individually and in strips.

The particular connector herein disclosed is suited for use in electronic or electrical assemblies that contain baseboards which are adapted to receive such connectors. The connectors are primarily intended to be secured in insulating baseboards which can constitute printed circuit boards having electrical conductive paths provided by conducting material attached to the insulating boards in patterns suited to the particular purposes of the circuits. The boards can also be formed of electrical conducting material providing electrical connection between all of the connectors secured to the board. In each case, separate leads are ultimately connected to the connectors to provide a desired pattern of electrical connections. As distinguished from the prior art connectors, the connectors grip the connected leads so tightly that they do not have to be dipped in molten solder to make the connections permanent.

The leads inserted in the connectors are firmly held therein so that they will not come out even if the connectors are subjected to rough handling. Further, as distinguished from the prior art connectors, sufficient openings need not be provided for free flow of solder into the wall portion of the terminal since there is no soldering operation.

Previously such elements have been formed by complicated machining or forming operations which, as compared with the hereinafter described method, made such elements relatively expensive to manufacture. However, it is now proposed by means of a limited number of simple punching, rolling, and shaping operations to produce such elements in mass quantities from readily available and inexpensive sheet metal stock, and to thereby considerably reduce the cost of such elements.

Accordingly, it is a primary object of this invention to provide a new and improved method for forming electrical connectors.

Another object of this invention is to provide such a method that requires only a limited number of simple forming operations.

Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part willbe obvious from the description, or may be learned by practice of the invention, the objects and advantages being realized and attained by means of the steps and combinations particularly pointed out in the appended claims.

To achieve the foregoing objects and in accordance with its purpose, as embodied and broadly described, this invention comprises a method of making an electrical connector from a strip of metallic material having longitudinal edges by forming from the strip at least one finger having a base substantially perpendicular to the longitudinal edges of the strip, the finger being integrally connected to the strip at the fingers base and having a free end opposite and parallel to the fingers base, bending the finger about its base so that the finger overlies the material of the strip and forms an acute angle with the material of the strip that it overlies, tubulating the strip so that the finger extends into the hollow of the tubulated strip and the longitudinal edges of the strip overlap, and shaping the tubulated strip to fonn a top connector portion around the finger and a bottom portion adjacent the top connector portion.

Preferably, a plurality of electrical connectors are formed from a strip of material having longitudinal edges by forming a plurality of longitudinally spaced fingers from the strip, the fingers being integrally connected to the strip at their bases, bending all of the fingers in the same direction so that they overlie the material of the strip and form longitudinally spaced openings in the strip, tubulating the strip so that the fingers extend into the hollow of the strip and the longitudinal edges of the strip approach each other, shaping the tubulated strip to form a top connector portion around the fingers, a bottom portion adjacent the top connector portion, and a waste portion attaching the top connector portion of each connector with the bottom portion of an adjacent connector and removing the waste portion to form individual connectors.

Desirably, a plurality of electrical connectors having two fingers in each connector, are formed from a strip of material having longitudinal edges by forming from the strip of material a first and second row of longitudinally aligned fingers, with the fingers of the second row being laterally aligned with the fingers of the first row, the fingers being integrally connected to the strip at their bases, bending all the fingers of both of the rows in the same direction so that they overlie the material of the strip and form adjacent pairs of laterally aligned openings in the strip; tubulating the strip so that the longitudinally edges of the strip overlap, shaping the areas longitudinally between the adjacent pairs of laterally aligned openings through the full width of the strip in said areas, to form adjacent connectors having a wide top connector portion around the fingers and a narrow bottom nose portion adjacent the top connector portion, forming a waste portion attaching the top connector portion of each connector with the bottom nose portion of an adjacent connector; and removing the waste portion to form individual connectors.

The tubulated stock is preferably shaped by a rotary die swaging operation to form a top connector portion and a bottom nose portion having a completely closed bottom end. Altematively, the bottom nose portion 24 need not be formed with a closed bottom end but can be formed with an opened bottom end. It is also preferred that any waste material be removed after the shaping operation to form a finished connector.

Two laterally aligned, spaced fingers are preferably formed in the strip and acted upon simultaneouslythroughout each operation to form a connector having two inwardly extending fingers. A plurality of such connectors are desirably formed in the metal strip by punching a first row having a plurality of equally spaced, identically sized fingers integrally connected to the strip at its base. A second parallel row of equally spaced, identically sized fingers is punched from the strip so that the fingers of the second row are laterally aligned with the fingers of the first row to form pairs of laterally aligned fingers and openings in the strip. The punching operation preferably bends the fingers upwardly in a direction substantially perpendicular to the plane of the strip.

The invention consists of the novel steps, combinations and improvements shown and described. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.

OF THE DRAWINGS FIG. 1 shows a perspective view of the stock after the fingers have been punched from the stock';

FIG. 2 represents a top view of the flat sheet metal stock on which the various operations required in the process are performed and particularly shows the stock as it is prepared for tubulating with imaginary lines drawn on the stock to describe its various portions;

FIG. 3 illustrates the tubulated metal strip and particularly shows how the fingers extend into the hollow of the tubulated stock;

FIG. 4 illustrates the tubular strip after it has been shaped to its final configuration and particularly shows the waste section of the stock that is to be removed to form the individual connectors;

FIG. 5 is a front view of the completed electrical connector;

FIG. 6 is a side view of the connector shown in FIG. 5; and

FIG. 7 is a top view of the electrical connector shown in FIGS. 5-6.

Referring first to FIGS. 5 through 7, it will be seen that the electrical connector 20 comprises a generally cylindrical sheet metal body which includes a top connector portion 22 containing two gripping fingers 28 and 29, a bottom nose portion 24 and an intermediate portion 25 connecting the nose portion 24 with the upper or top connector portion 22. The top connector portion 22 is intended to be inserted into any one of a plurality of circular apertures contained in a base board 23.

The diameter of top portion 22 of the connector is greater than that of nose portion 24. Intermediate portion 25, which connects top portion 22 to nose portion 24, thus comprises a curved shoulder 26 having a convex surface 27 which provides a gradual expansion in the diameter of the connector. Although the connector can be made of any suitable electrical conducting material, it is preferably made of such metals as beryllium copper, bronze or brass alloys.

The nose portion 24 of connector has a cylindrical section 30 connected at its upper end to shoulder 26. The bottom end of nose portion 24 is closed by a solid end 32 having a concave surface 34. The solid, closed end 32 is integrally connected to the cylindrical portion 30 by a convex portion 36.

Two holding or gripping fingers 28 and 29 are integrally formed in top connector portion 22 for gripping at least one electrical lead of various types and sizes, including, for example, wires, tube rungs, resistor leads, or other compound leads. Top connector portion 22 has a top opening 33, defined by top edge 37, for receiving the electrical lead.

Wiring leads are inserted into top opening 33 of connector 20. The ends of the leads are stripped of insulation in order to provide electrical connection with the connector.

Gripping fingers 28 and 29 are generally of elongated rectangular configuration. Each finger 28 has a base 38 integrally connected to the main body of the connector at top edge 37 of top portion 22, a free end opposite and parallel to base 38, and elongatedparallel sides 58 and 60 that connect free end 40 with base 38. Similarly, each finger 29 has a base 39 integrally connected to the main body of the connector at the upper edge 37 of top portion 22, a free end 41 opposite and parallel to base 39, and elongated parallel sides 62 and 64 that connect free end 41 with base 39.

The gripping fingers 28 and 29 extend downwardly into connector 20 in converging cantilever relation toward the closed end 32 of connector 20 with the free ends 40 and 41 of the fingers 28 and 29 engaging or substantially engaging one another. As seen in FIGS. 6 and'7, the bottom free ends 40 and 41 of gripping fingers 28 and 29 can be offset from each other. This configuration enables the leads to be positively supported by the gripping fingers even though the supporting free ends of one or both of the gripping fingers are not in full engagement with the leads.

The configuration of gripping fingers 28 and 29 and their resilient interreaction with top portion 22 of the connector 20 allow the connector to hold electrical leads of substantially varying size. The connector generally accommodates at least one lead which can be readily inserted into connector 20 and once inserted is held firmly therein. It will be understood that leads of varying sizes can be inserted and gripped in a single connector.

Closed bottom end 32 of nose portion 24 provides a lead stop, which allows the leads to be inserted into the connector without regard to placement until they engage the bottom. Closed end 32 thus insures uniformity of location of the leads and also insures that the inserted leads do not present protruding ends which would have to be cut off by an additional clipping or sanding operation. This feature eliminates an additional cut-off operation necessary in the production of many prior art connectors.

The bottom end of nose portion 24 need not be closed but can be opened and as long as the diameter of the opening is less than the diameter of the inserted lead, the bottom end of nose portion 24 will perform the functions of insuring uniformity of location of the leads and insuring that the inserted leads do not present protruding ends.

When the leads have been inserted, they are firmly held in the connector and will not come out even though the baseboard is subjected to rough handling during subsequent operations. The connection provided by the gripping fingers is sufficient without soldering, and thus it is contemplated that the leads will not be permanently soldered in connector 20 in a subsequent operation. This eliminates another costly step of many prior art connector production processes.

Contrary to many prior art connectors which are comprised of two or more separate parts and have an inner spring and an outer case or shell, the connector of this invention is a unitary, integral strip of material. This unitary connector provides the advantage of not having internal secondary electrical connections which result in greater electrical resistance. Greater electrical resistance is found in the prior art connectors where there is a first electrical connection between the lead and the inner spring and a second electrical connection between the inner spring and outer case.

Now referring to FIGS. 1 through 4, it will be seen that the above-described connectors are readily and conveniently formed from sheet stock by subjecting such stock to a limited number of simple, uncomplicated slitting, punching, rolling, and forming operations.

In accordance with the invention, a plurality of electrical connectors having two fingers in each connector are formed from a sheet or strip of metal stock by forming from the strip of material a first and second row of longitudinally aligned fingers, with the fingers of the second row being laterally aligned with the fingers of the first row, and with the fingers being integrally connected to the strip at their bases. As here embodied, a metal strip 42 is initially punched or lanced to provide it with a first straight longitudinal row containing a plurality of spaced longitudinally aligned fingers 28 and a second parallel row containing an equal number of spaced longitudinally aligned fingers 29, with the fingers of the second row being laterally aligned with the fingers of the first row.

Metal strip 42 is of elongated rectangular shape. The length of the strip 42 is defined by longitudinal parallel edges 46 and 48 and the width by shorter transverse edges 47 and 49 perpendicular to longitudinal edges 46 and 48.

Fingers 28 and 29 are integrally connected to metal strip 42 at their respective bases 38 and 39. These bases are parallel to the transverse edges 47 and 49 of metal strip 42. Fingers 28 and 29 are preferably identical in size and configuration and generally are of elongated rectangular configuration. Each finger 28 is formed with elongated longitudinal sides 58 and 60 that are parallel to longitudinal edges 46 and 48 of metal stock 42. Similarly, each finger 29 is formed with elongated longitudinal sides 62 and 64 that are parallel to the longitudinal edges 46 and 48 of metal stock 42.

Fingers 28 and 29 are formed with respective free ends 40 and 41 which are parallel to their respective bases 38 and 39. Each finger 28 is evenly spaced from its next adjacent finger 28, and in the same manner each finger 29 is evenly spaced from its next adjacent finger 29.

As shown in FIG. 1, the force of the punching operation bends each finger 28 and 29 in the same upward direction, substantially perpendicular to the plane of the stock and leaves two parallel rows of rectangular openings 44 and 45 to form adjacent pairs of laterally aligned openings in stock material 42. Rectangular openings 44 and 45 have respective transverse edges 66 and 68 that correspond to free ends 40 and 41 of fingers 28 and 29. The opposing transverse edges of rectangular openings 44 and 45 are defined by respective bases 38 and 39. Rectangular opening 44 has longitudinal sides 70 and 72, that correspond to sides 58 and 60 of finger 28. Similarly, rectangular opening 45 has longitudinal sides 74 and 76 that correspond to sides 62 and 64 of finger 29. Although each finger 28 and 29 can be separately punched, it is preferred, in accordance with the present process, to simultaneously punch all of fingers 28 and 29 in one operation.

To aid in the description of the areas formed by the punching operation, imaginary lettered lines have been placed on FIG. 2. Except as hereafter indicated, these lines are not intended to represent any cutting or folding lines but are used only for descriptive purposes.

The areas longitudinally between each of the adjacent pairs of laterally aligned openings and extending through the full width of the metal strip 42 are those areas of the strip that are worked to form the body of the connector pins. More particularly, this worked area is rectangular in shape and is preferably defined by the metal stock that is between first imaginary line c-c that extends from longitudinal edge 46 of metal strip 42 to longitudinal edge 48 of strip 42 and is to the left of and parallel to imaginary line a-a which passes through base 38 of finger 28 and base 39 of corresponding finger 29, and second imaginary line d-d that extends from edge 46 to edge 48 and is to the left of and parallel to imaginary line b-b which passes through transverse edge 66 of the next adjacent longitudinally spaced opening 44 and the transverse edge 68 of corresponding laterally alignedopening 45'. Lines d-d and b-b extend through the width of the strip. The worked area is indicated generally by numeral 78. It will be understood by those skilled in the art that identical areas 78 are formed between each of the adjacent pairs of laterally aligned openings of the strip.

The first laterally aligned pair of openings at the righthand end of the metal strip, shown on FIG. 2 as openings 44" and 45", is, of course, not paired with an adjacent pair of laterally aligned openings to its right. However, the area and shape of the material between the imaginary line c-c extending from longitudinal edge 46 to longitudinal edge 48 and to the left of and parallel to imaginary line a-a which passes through the bases 38 and 39 of the first pair of fingers at the righthand end of the strip, and the transverse edge 47 of that end of the metal strip are the same as those between each of the adjacent pairs of laterally aligned openings of the strip.

The first pair of laterally aligned openings at the lefthand end of the strip is also not paired with an adjacent pair of laterally aligned openings to its left. Although the transverse edges 66 and 68 of this first pair of openings can be contiguous with transverse edge 49 of metal strip 42, it is desirable to have this first pair of openings spaced from edge 49 to provide added support duringthe punching operation.

In accordance with the invention, the gripping fingers are bent so that they overlie the material of the strip and form adjacent pairs of laterally aligned openings in the strip. As here embodied, the upstanding fingers 28 and 29 are bent about their respective bases 38 and 39 which act as fulcrums so that the fingers overlie a portion of the areas 78 between the adjacent pairs of laterally aligned openings and complete the formation of the rectangular openings. This bending is achieved by applying a rotary force to bottom free ends 40 and 41 of gripping fingers 28 and '29 so that the fingers form an acute angle with the material of the strip that the fingers overlie. This force acts perpendicular to the base of the gripping fingers. Although each finger can be separately bent to the position shown in FIGS. 2 and 3, it is preferred to simultaneously bend all the gripping fingers in one operation by means of a tool that engages bottom free ends 40 and 41 of all gripping fingers 28 and 29. The portion of area 78 that the fingers overlie forms top portion 22 of the connector while the remaining portion of area 78 forms the intermediate and bottom nose portions of the connector.

In accordance with the invention, metal strip 42 is tubulated so that fingers 28 and 29 extend into the hollow of the tubulated strip. As here embodied, the strip is bent or rolled about a longitudinal axis by applying an upward rotary force that abts in substantially the same direction as the punching force that produced the fingers. The strip is rolled through an arc exceeding 360 so that elongated longitudinal edges 46 and 48 of metal strip 42 overlap and fingers 28 and 29 extend into the hollow of the tubulated strip to engage or substantially engage each other at their free ends 40 and 41. The extent of the overlap is, however, not great, so that the edges 46 and 48 do not overlie fingers 28 and 29.

By varying the acute angle formed between the fingers and the material of the strip that the fingers overlie, and by varying the extent of overlap of edges 46 and 48, it is possible to correspondingly vary the amount of pre-load or tension exerted on the fingers. Advantageously, this enables the fingers to be deflected an amount sufficient to keep them under constant tension which in turn results in considerably improved electrical contact.

The tubulated stock is then given its final configuration by a rotary die swaging operation. The specific die used is designed to produce connectors, each of which has a substantially cylindrical nose portion 24 having a solid closed end 32, an intermediate portion 25 comprising a curved shoulder 26 having a convex surface 27, and a larger cylindrical top portion 22, all formed from the stock material in area 78. Although each connector may be separately shaped by a die having a single shaping cavity it is preferred to use a die having a multiplicity of identically recurring cavities each having the desired shape.

The swaging operation is particularly suited for shaping tubulated stock and is uniquely suited for obtaining finished round cross-sectional shapes in the tubulated stock. Thus, the rotating dies used in the swaging operation can readily form in one operation a wide cylindrical top connector portion 22, an intermediate portion 25 having a convex surface 27, and a narrow bottom nose portion 24 having a cylindrical section 30 connected at its upper end to the intermediate portion 25 and a solid closed end 32 having a concave surface 34 which is integrally connected to the cylindrical portion 30 by a convex portion 36. Because swaging is actually performed more by pressure than by blows, there is a flow and readjustment of the grains of the swaged material which enables a solid closed end 32 to be formed simultaneously with the shaping of substantially hollow sections such as top connector portion 22, intermediate portion 25 and cylindrical portion 30. The swaging operation thereby eliminates multiple forming steps that would ordinarily be needed to form a solid closed portion and a hollow portion. By using a swaging operation, it is also possible to provide the connectors with rings or shoulders that are desirable for wire wrapping.

Between the closed bottom end 32 of a first connector and the top portion 22 of the connector adjacent to it, the swaging die forms a waste portion 50 between the two connectors. Waste portion 50, FIG. 4, comprises a substantially closed cup segment 52 attached to the bottom end of the first connector and a punched cylindrical segment generally 53 having two axially extending arms generally 54 and 56 attaching the cup segment 52 with the top portion 22 of the adjacent connector.

Arm 54 is comprised of the material laterally between laterally aligned openings 44 and 45 More particularly, arm 54 is comprised of that portion of the stock between side 72 of opening 44 and side 74 of opening 45 which lies between imaginary line b-b and imaginary line c-c' which extends from longitudinal edge 46 to longitudinal edge 48 of metal stock 42 and is to the left of and parallel to imaginary line a-a which passes through bases 38 and 39 that define the respective opposing transverse edges of laterally aligned openings 44 and 45'. This area is indicated generally by numeral 80, FIG. 2. Arm 56 is comprised of segment 82 which extends between edge 46 of metal strip 42 and side of opening 44 and segment 84 which extends between side 76 of opening 45' and edge 48 of metal stock 42. Segments 82 and 84 are brought into overlapping relationship to form arm 56 when the stock is tubulated.

Individual electrical connectors are separated from the tubulated shaped stock by removing waste section 50 in a cutting operation. The top portion of the connector is separated from the stock preferably by cutting along imaginary line c-c, FIG. 2, which lies parallel to and closely adjacent line a-a. Cutting along line cc, as shown in FIG. 6, results in top edge 37 of the connector being spaced slightly above the bases 38 and 39 of fingers 28 and 29, and insures that the cutting operation will not sever the fingers from the connector. The bottom portion of the connector is separated from the stock by cutting preferably along an imaginary line d-d parallel to and closely adjacent line b-b. Cutting along lines c-c, d-d, and primed lines c-c and dd results in the removal of waste portions 50.

It will be apparent to those skilled in the art that the position of the lines of cut may be varied without deviating from the scope and spirit of this invention so long as they sever the connector from the stock.

The swaging operation produces a tight seam at overlapped edges 46 and 48 and thereby forms a substantially closed cylindrical connector that is only open at its top portion 22 through top opening 33. The bottom nose portion 24 of the connector can be easily inserted into a baseboard since it is of smaller diameter than the baseboard opening. The concave surface of intermediate portion 25 permits an easy transition for the insertion of top connector portion 22 into the baseboard. As the top connector portion 22 is pushed downwardly into the baseboard, overlapping edges 46 and 48 are forced into a greater overlap. However, because of the resilient nature of the metallic material, the overlapping edges tend to resume their initial overlap and thus secure the connector in the baseboard opening.

An important advantage of the present process is that the various steps used in forming the electrical connectors can be carried out on a single sheet of stock while the connectors being formed from that stock are held together by the waste segment of the stock until the connectors are completely formed and severed. The process is thus adapted for economical and practical mass production of electrical connectors.

The invention in its broader aspects is not limited to the specific details shown and described but departures may be made from such details without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A method of making an electrical connector from a strip of metallic material having longitudinal edges by forming from the strip at least one finger having a base substantially perpendicular to the longitudinal edges of the strip, the finger being integrally connected to the strip at the fingers base and having a free end opposite and parallel to the fingers base, bending the finger about its base so that the finger overlies the material of the strip and forms an acute angle with the material of the strip that it overlies, tubulating the strip so that the finger extends into the hollow of the tubulated strip and the longitudinal edges of the strip overlap, shaping the tubulated strip to form a top connector portion around the finger, a waste portion extending outwardly from the top connector portion and a bottom portion adjacent the top connector portion, and removing the waste portion to form the connector.

2. A method for making a plurality of electrical connectors from a strip of material having longitudinal edges comprising forming a plurality of longitudinally spaced fingers from the strip of material, said fingers being integrally connected to the strip at their base, bending all of the fingers in the same direction so that they overlie the material of the strip and form longitudinally spaced openings in the strip, tubulating the strip so that the fingers extend into the hollow of the strip, and the longitudinal edges of the strip approach each other, shaping the tubulated strip to form a top connector portion around said fingers, a bottom portion adjacent said top connector portion, and a waste portion, and removing the waste portion to form individual connectors.

3. A method for making a plurality of electrical connectors from a strip of material having longitudinal edges comprising forming from the strip of material a first and second row of longitudinally aligned fingers, with the fingers of the second row being laterally aligned with the fingers of the first row, the fingers being integrally connected to the strip at their bases, bending all the fingers of both of the rows in the same direction so that they overlie the material of the strip and form adjacent pairs of laterally aligned openings in the strip; tubulating the strip so that the longitudinal edges of the strip overlap, shaping the areas longitudinally between the adjacent pairs of laterally aligned openings through the full width of the strip in said areas, to form adjacent connectors having a wide top connector portion around the fingers and a narrow bottom nose portion adjacent the top connector portion; forming a waste portion attaching the top connector portion of each connector with the bottom nose portion on an adjacent connector, and removing the waste portion to form individual connectors.

4. The method according to claim 3 which includes forming said laterally aligned fingers in identical size and configuration.

5. The method according to claim 4, wherein the fingers are formed by a punching operation that punches the fingers from the strip of metal stock and bends the fingers upwardly in a direction substantially perpendicular to the plane of the strip.

6. The method according to claim 5 wherein the upwardly bent fingers are further bent so that the fingers overlie the material of the strip by applying a rotary force to the free ends of the fingers that acts in a direction perpendicular to the base of the fingers.

7. The method according to claim 4 wherein the strip is tubulated by rolling it through an arc exceeding 360 so that the edges of the strip overlap, the extent of said overlap being insufficient to cause the overlapped edges to overlie the fingers.

8. The method according to claim 4 wherein the shaping step includes forming a shoulder portion in the outside wall of the tubulated strip between said narrower nose portion and said wider top connector portion, said shoulder portion providing a gradual expansion in the diameter of the connec- I01.

9. The method according to claim 8 wherein the shaping includes the forming of a closed end on the bottom nose portion of each connector.

10. The method according to claim 4 wherein the shaping is a rotary die swaging operation. 

1. A method of making an electrical connector from a strip of metallic material having longitudinal edges by forming from the strip at least one finger having a base substantially perpendicular to the longitudinal edges of the strip, the finger being integrally connected to the strip at the finger''s base and having a free end opposite and parallel to the finger''s base, bending the finger about its base so that the finger overlies the material of the strip and forms an acute angle with the material of the strip that it overlies, tubulating the strip so that the finger extends into the hollow of the tubulated strip and the longitudinal edges of the strip overlap, shaping the tubulated strip to form a top connector portion around the finger, a waste portion extending outwardly from the top connector portion and a bottom portion adjacent the top connector portion, and removing the waste portion to form the connector.
 2. A method for making a plurality of electrical connectors from a strip of material having longitudinal edges comprising forming a plurality of longitudinally spaced fingers from the strip of material, said fingers being integrally connected to the strip at their base, bending all of the fingers in the same direction so that they overlie the material of the strip and form longitudinally spaced openings in the strip, tubulating the strip so that the fingers extend into the hollow of the strip, and the longitudinal edges of the strip approach each other, shaping the tubulated strip to form a top connector portion around said fingers, a bottom portion adjacent said top connector portion, and a waste portion, and removing the waste portion to form individual connectors.
 3. A method for making a plurality of electrical connectors from a strip of material having longitudinal edges comprising forming from the strip of material a first and second row of longitudinally aligned fingers, with the fingers of the second row being laterally aligned with the fingers of the first row, the fingers being integrally connected to the strip at their bases, bending all the fingers of both of the rows in the same direction so that they overlie the material of the strip and form adjacent pairs of laterally aligned openings in the strip; tubulating the strip so that the longitudinal edges of the strip overlap, shaping the areas longitudinally between the adjacent pairs of laterally aligned openings through the full width of the strip in said areas, to form adjacent connectors having a wide top connector portion around the fingers and a narrow bottom nose portion adjacent the top connector portion; forming a waste portion attaching the top connector portion of each connector with the bottom nose portion on an adjacent connector, and removing the waste portion to form individual connectors.
 4. The method according to claim 3 which includes forming said laterally aligned fingers in identical size and configuration.
 5. The method according to claim 4, wherein the fingers are formed by a punching operation that punches the fingers from the strip of metal stock and bends the fingers upwarDly in a direction substantially perpendicular to the plane of the strip.
 6. The method according to claim 5 wherein the upwardly bent fingers are further bent so that the fingers overlie the material of the strip by applying a rotary force to the free ends of the fingers that acts in a direction perpendicular to the base of the fingers.
 7. The method according to claim 4 wherein the strip is tubulated by rolling it through an arc exceeding 360* so that the edges of the strip overlap, the extent of said overlap being insufficient to cause the overlapped edges to overlie the fingers.
 8. The method according to claim 4 wherein the shaping step includes forming a shoulder portion in the outside wall of the tubulated strip between said narrower nose portion and said wider top connector portion, said shoulder portion providing a gradual expansion in the diameter of the connector.
 9. The method according to claim 8 wherein the shaping includes the forming of a closed end on the bottom nose portion of each connector.
 10. The method according to claim 4 wherein the shaping is a rotary die swaging operation. 